The Suburban Rail Loop (SRL) is a fully automated rapid transit system under construction in Melbourne, Victoria, Australia. The project would connect suburbs 15–25 kilometres (9.3–15.5 mi) from the Central Business District (CBD) along an approximately 90 km (56 mi) corridor. The two main stages, SRL East and SRL North, would together form a single 60 km (37 mi) orbital line with 13 stations between Cheltenham and Melbourne Airport, connecting eight existing Melbourne rail lines. The SRL Airport component, in the city's west, would be formed by the separate Melbourne Airport rail link project, which began construction in 2022.